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Title: Integrated modeling applications for tokamak experiments with OMFIT

Abstract

We developed one modeling framework for integrated tasks (OMFIT) is a comprehensive integrated modeling framework which will enable physics codes to interact in complicated workflows, and support scientists at all stages of the modeling cycle. The OMFIT development follows a unique bottom-up approach, where the framework design and capabilities organically evolve to support progressive integration of the components that are required to accomplish physics goals of increasing complexity. OMFIT provides a workflow for easily generating full kinetic equilibrium reconstructions that are constrained by magnetic and motional Stark effect measurements, and kinetic profile information that includes fast-ion pressure modeled by a transport code. It was found that magnetic measurements can be used to quantify the amount of anomalous fast-ion diffusion that is present in DIII-D discharges, and provide an estimate that is consistent with what would be needed for transport simulations to match the measured neutron rates. OMFIT was used to streamline edge-stability analyses, and evaluate the effect of resonant magnetic perturbation (RMP) on the pedestal stability, which have been found to be consistent with the experimental observations. Moreover, the development of a five-dimensional numerical fluid model for estimating the effects of the interaction between magnetohydrodynamic (MHD) and microturbulence, and itsmore » systematic verification against analytic models was also supported by the framework. OMFIT was used for optimizing an innovative high-harmonic fast wave system proposed for DIII-D. For a parallel refractive index n(parallel to) > 3, the conditions for strong electron-Landau damping were found to be independent of launched n(parallel to) and poloidal angle. OMFIT has been the platform of choice for developing a neural-network based approach to efficiently perform a non-linear multivariate regression of local transport fluxes as a function of local dimensionless parameters. Transport predictions for thousands of DIII-D discharges showed excellent agreement with the power balance calculations across the whole plasma radius and over a broad range of operating regimes. Concerning predictive transport simulations, the framework made possible the design and automation of a workflow that enables self-consistent predictions of kinetic profiles and the plasma equilibrium. It is found that the feedback between the transport fluxes and plasma equilibrium can significantly affect the kinetic profiles predictions. Finally, such a rich set of results provide tangible evidence of how bottom-up approaches can potentially provide a fast track to integrated modeling solutions that are functional, cost-effective, and in sync with the research effort of the community.« less

Authors:
 [1];  [1];  [1];  [2];  [3];  [4];  [1];  [5];  [6];  [2];  [7];  [1];  [2];  [8];  [9];  [10];  [11];  [2];  [1];  [1] more »;  [1];  [1];  [1];  [1] « less
  1. General Atomics, San Diego, CA (United States)
  2. Univ. of California, San Diego, CA (United States)
  3. Chinese Academy of Sciences (CAS), Beijing (China). Inst. of Plasma Physics
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
  6. Arizona State Univ., Phoenix, AZ (United States)
  7. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  8. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  9. Univ. of Texas, Austin, TX (United States)
  10. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)
  11. Hope College, Holland, MI (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1295131
DOE Contract Number:  
AC05-00OR22725; FG02-95ER54309; FG02-07ER54917; AC05-060R23100; AC02-09CH1146; FG02-06ER54871; AC52-07NA27344
Resource Type:
Journal Article
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 55; Journal Issue: 8; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; OMFIT; integrated; modeling; DIII-D tokamak; COLLISIONALITY REGIME; CYCLOTRON WAVES; PLASMAS; SIMULATION; TRANSPORT; STABILITY; CODE; PEDESTAL; PHYSICS; MODES

Citation Formats

Meneghini, O., Smith, S. P., Lao, L. L., Izacard, O., Ren, Q., Park, J. M., Candy, J., Wang, Z., Luna, C. J., Izzo, V. A., Grierson, B. A., Snyder, P. B., Holland, C., Penna, J., Lu, G., Raum, P., McCubbin, A., Orlov, D. M., Belli, E. A., Ferraro, N. M., Prater, R., Osborne, T. H., Turnbull, A. D., and Staebler, G. M. Integrated modeling applications for tokamak experiments with OMFIT. United States: N. p., 2015. Web. doi:10.1088/0029-5515/55/8/083008.
Meneghini, O., Smith, S. P., Lao, L. L., Izacard, O., Ren, Q., Park, J. M., Candy, J., Wang, Z., Luna, C. J., Izzo, V. A., Grierson, B. A., Snyder, P. B., Holland, C., Penna, J., Lu, G., Raum, P., McCubbin, A., Orlov, D. M., Belli, E. A., Ferraro, N. M., Prater, R., Osborne, T. H., Turnbull, A. D., & Staebler, G. M. Integrated modeling applications for tokamak experiments with OMFIT. United States. doi:10.1088/0029-5515/55/8/083008.
Meneghini, O., Smith, S. P., Lao, L. L., Izacard, O., Ren, Q., Park, J. M., Candy, J., Wang, Z., Luna, C. J., Izzo, V. A., Grierson, B. A., Snyder, P. B., Holland, C., Penna, J., Lu, G., Raum, P., McCubbin, A., Orlov, D. M., Belli, E. A., Ferraro, N. M., Prater, R., Osborne, T. H., Turnbull, A. D., and Staebler, G. M. Wed . "Integrated modeling applications for tokamak experiments with OMFIT". United States. doi:10.1088/0029-5515/55/8/083008.
@article{osti_1295131,
title = {Integrated modeling applications for tokamak experiments with OMFIT},
author = {Meneghini, O. and Smith, S. P. and Lao, L. L. and Izacard, O. and Ren, Q. and Park, J. M. and Candy, J. and Wang, Z. and Luna, C. J. and Izzo, V. A. and Grierson, B. A. and Snyder, P. B. and Holland, C. and Penna, J. and Lu, G. and Raum, P. and McCubbin, A. and Orlov, D. M. and Belli, E. A. and Ferraro, N. M. and Prater, R. and Osborne, T. H. and Turnbull, A. D. and Staebler, G. M.},
abstractNote = {We developed one modeling framework for integrated tasks (OMFIT) is a comprehensive integrated modeling framework which will enable physics codes to interact in complicated workflows, and support scientists at all stages of the modeling cycle. The OMFIT development follows a unique bottom-up approach, where the framework design and capabilities organically evolve to support progressive integration of the components that are required to accomplish physics goals of increasing complexity. OMFIT provides a workflow for easily generating full kinetic equilibrium reconstructions that are constrained by magnetic and motional Stark effect measurements, and kinetic profile information that includes fast-ion pressure modeled by a transport code. It was found that magnetic measurements can be used to quantify the amount of anomalous fast-ion diffusion that is present in DIII-D discharges, and provide an estimate that is consistent with what would be needed for transport simulations to match the measured neutron rates. OMFIT was used to streamline edge-stability analyses, and evaluate the effect of resonant magnetic perturbation (RMP) on the pedestal stability, which have been found to be consistent with the experimental observations. Moreover, the development of a five-dimensional numerical fluid model for estimating the effects of the interaction between magnetohydrodynamic (MHD) and microturbulence, and its systematic verification against analytic models was also supported by the framework. OMFIT was used for optimizing an innovative high-harmonic fast wave system proposed for DIII-D. For a parallel refractive index n(parallel to) > 3, the conditions for strong electron-Landau damping were found to be independent of launched n(parallel to) and poloidal angle. OMFIT has been the platform of choice for developing a neural-network based approach to efficiently perform a non-linear multivariate regression of local transport fluxes as a function of local dimensionless parameters. Transport predictions for thousands of DIII-D discharges showed excellent agreement with the power balance calculations across the whole plasma radius and over a broad range of operating regimes. Concerning predictive transport simulations, the framework made possible the design and automation of a workflow that enables self-consistent predictions of kinetic profiles and the plasma equilibrium. It is found that the feedback between the transport fluxes and plasma equilibrium can significantly affect the kinetic profiles predictions. Finally, such a rich set of results provide tangible evidence of how bottom-up approaches can potentially provide a fast track to integrated modeling solutions that are functional, cost-effective, and in sync with the research effort of the community.},
doi = {10.1088/0029-5515/55/8/083008},
journal = {Nuclear Fusion},
issn = {0029-5515},
number = 8,
volume = 55,
place = {United States},
year = {2015},
month = {7}
}